Car Parking Chains 16ALT 20ALT 24ALT

Description

Product Overview

Automated multi-storey car parking systems — both puzzle-type stacker systems and fully automated robotic garages — rely on roller chains for vehicle lifting, lateral transfer, and pallet positioning. These chains operate under conditions that differ significantly from general industrial conveying: loads are heavy (1,500–3,000 kg per vehicle), cycles are frequent (10–50 lifts per hour in high-throughput facilities), and positioning accuracy is critical — a parking system that mis-positions a vehicle pallet by even a few centimetres creates a collision risk that causes both structural damage and safety incidents.

The ALT designation (from the German ‘Autolift’, meaning car lift) identifies chains specifically designed and certified for this application. The key differences from standard roller chains are: bolted link plate construction rather than peened pin ends, allowing the chain to be inspected and individual links replaced without chain cutting; precision-bored bolt holes with consistent diameter tolerance for reliable bolt fitting across the chain’s full length; and higher fatigue ratings than standard chains of equivalent pitch, reflecting the high-cycle loading profile of parking system drives.

ALT series parking chains — precision bolt-hole construction for automated vehicle lift systems

ALT Chain Specifications

Three ALT pitch sizes cover the range of parking system designs currently installed globally. 16ALT (25.4mm pitch) is the most widely used size in compact puzzle-type stacker systems. 20ALT (31.75mm pitch) is specified for medium-duty platforms carrying heavier vehicles and SUVs. 24ALT (38.1mm pitch) is used in large-format robotic garage systems where the drive loads and cycle counts are highest.

Why ALT Chain is Specified for Vehicle Lifting

Standard roller chains are retained by peened pin ends — the pin is pressed through the outer link plates and its ends are mechanically deformed to create a retaining flange. This works well in standard applications but makes individual link inspection and replacement impractical without cutting the chain. ALT chains use threaded bolts through the link plates, retained by nuts on the outer face. The bolt can be removed without any cutting tool, allowing a single worn or damaged link to be replaced in place on the chain run — a critical maintenance capability for parking systems that must return to service quickly after a fault.

The precision bolt holes in ALT chains serve a second function: they allow calibrated torque tightening of the bolts, which pre-loads the link plates in compression and raises the chain’s fatigue limit significantly above what peened construction achieves at the same plate thickness. This pre-load is specified in the chain’s installation documentation and should be verified at the initial installation and at each maintenance interval — inadequate bolt torque reduces the chain’s effective fatigue rating and voids the manufacturer’s certification.

Indoor and Outdoor Installation Considerations

Multi-storey car parks divide into two primary structural types: enclosed air-conditioned structures and open-sided or semi-open structures exposed to the external environment. Enclosed structures present a relatively benign environment for ALT chains — humidity is controlled, temperature range is moderate, and the chains can be lubricated with standard mineral oil on a regular maintenance schedule. Open structures present a far more challenging scenario: the chains are exposed to rain, temperature cycling across freeze-thaw transitions, road salt aerosol from vehicles, and UV radiation. These conditions require ALT chains with corrosion-resistant surface treatment — zinc phosphating followed by a sealing coat is the minimum for outdoor applications; hot-dip galvanising or stainless steel pin options are specified for coastal locations and regions where road salt use is heavy.

Both indoor and outdoor installations require the same positioning accuracy standard: the chain must maintain its effective pitch to within ±0.3% of nominal across the full chain length at the point of pallet position sensing. This requires careful chain elongation monitoring — elongation beyond 1.5% of nominal pitch length triggers replacement to prevent positioning errors that could misalign the vehicle pallet with the structural guides.

Maintenance Regime and Replacement Intervals

ALT chains should be inspected every 3 months in high-cycle facilities (above 20 vehicle movements per parking space per day). Key inspection points are: pin bolt torque (re-torque to specification if below minimum); visible corrosion at plate surfaces and bolt heads; chain pitch measurement using a calibrated chain wear gauge; and roller condition — cracked or flat-spotted rollers indicate shock overloading that may require investigation of the drive and braking system.

Chain replacement should be scheduled when pitch elongation reaches 1.5% of nominal, or when any link shows visible cracking at the plate edges, or when the bolt removal torque during inspection falls below 60% of the installation specification (indicating the bolt has loosened beyond recovery). Replace sprockets simultaneously with chains — worn sprockets create accelerated wear in new chains from the first shift.

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